Improvement in the manufacture of steel



3 Sheets-Sheet 1` M. J. HAMILTON.

Manfacture of Steel. No. 195,891. Patented Oct. 9, 1877.

RATcR .6;

".PETERS, PHOTO-JHQGRAPMER. WASHINGTON. D Cv 3 Sheets-Sheet 2.

M. J. HAMILTON. Manufacture of Steel.

N0.195,891`. Patented oct. 9, 1871.

NJEIERS. PHoTO-LITHOGRAMFR wAsluNGw. L" C Smarts prirent Genion.,

MARK JOHN HAMILTON, OF sr. Louis, Missoung,`

IMPROVEMENT llN THE IVIANUFACTURE OF STEEL.

Specification forming part of Letters Patent No. 195,891, dated October9, 1877 application filed November' 10,- 1876.

Tol all whom it may' concemf Be it known that I, MARK JOHN HAMiL- ioN,of St. Louis, in the State of Missouri, have invented a new and usefulProcess of Manufacturing Steel, and apparatus connected therewith, ofwhich I hereby declare the following to be a full, clear, and precisedescription, which will enable others skilled in the art to which myinvention appert'ains to comprehend my process and construct anapparatus necessary to put the same in effect, reference being hadV tothe accompanying drawings, forming part of this specification, of which-Figure 1 is a central sectional and detailed elevation of the generatorand attachments, and of the purifier 5 Fig. 2, asimilar view of theconverter and attachments; Fig, 3, a bottom plan from beneath of theconverter, the bottom ofthe lowermost inclosing casing being removed 5Figxt, a top plan of the converter and attachments 5 and Fig. 5, asimilar view of the generator and purifier.

Similar letters of reference indicate corresponding parts wherever used.

For the better coml'irehension of my inventionI will iirst proceed todescribe the difficulties whiclrnow exist in the manufacture of Bessemerand other steel from certain kinds of ore, and will explain at somelength the processes now in .,vogue, setting forth their disadvantages.

The pig metal used in the lmanufacture of Bessemer steel is sineltedfrom the purer and richer ores, and must contain a considerable amountof carbon, and also some silicon, so as to cause combustion in themolten mass when atmospheric air -is blown through it, and` generate theintenseheat required to keep decarburized metal in the liquid state. It

'must alsobe almost entii-'ely free from phosphorus and sulphur,- asthey cannot be eliminated by the present process on account of theimpossibilityof using iluXes; lhe lower grades of pig-iron are,therefore, excluded from the manufacture of Bessemer steel, and thelimits within which it can be made consequently narrow.

It is also evident that Bessemer steel cannot be made in those sectionsof the country which yield only ores containing large percentages ofphosphorus or sulphur, no matter how rich they may be in metallic iron.It therefore becomes of the greatest importance to invent a process andapparatus by which these ores and the lower grades of pig-iron can bebrought within the limits of steel-manufacture.

The object of my invention is to cheapen the production and extend thefield of steelmanufacture by utilizing low grades of pig metal and suchrich ores as are now excluded on account of the presence in them ofphosphorus or sulphur.

In the ordinary process, pig metal must be again melted in a cupola, andin the molten state charged into the converter, which has been broughtinto a nearly-horizontal position. Atmospheric air must then be blownthrough the tuyeres at a high pressure, and the converter brought to avertical position. rIhe blast is kept up until the carbon, silicon,etc., are removed, or very nearly so, by oxidation, when the converteris again brought to the horizontal position, and the spiegeleisen, in adetermined proportion and in the molten state, poured into it. In a fewmoments the carbon of the spiegeleisen is disseminated throughout themass, the iron converted into steel, and iinally cast into ingots.

The present construction of the converters makes it impossible to employfluxes, either in the powdered or gaseous form, and hence no impuritiescan be removed except such as can be oxidized out, and therefore thepresent impossibility of removing the phosphorus and sulphi and thegreat Waste caused by the formation of silicate with the impurities.

My present invention is designed to obviate such difficulties anddefects.

The following is a description of the mechanical construction of myapparatus:

Referring to Fig. l of the drawing', A is the generator or vessel inwhich the fuel is placed and the carbonic-oxide gas generated. l) is acircular pipe surrounding the generator at its base, and connected withthe blast-engine through the pipe D", Fig. 5. j j are tuyeres connectingthe circular pipe D with the interior of the generator. t' is aman-hole. His pipe leading' from the generator A to the purifier I,having in it a cock, H'. E is a gastight valve-box, in which aslide-valve, E', moves, cutting oif and openn g communication betweenthe generator A and the chargingcylinder T, located above it. This valveis moved by the hand-lever C or other device.

F is a poker to loosen the fuel in case it should j am in the cone Z'.It also is controlled by a hand-lever, F', or other device, and movesthrough a gas-tight stuiiing-box. The pipe G, provided with the cock G',communicates with the interior of the generator A, and with that of thecharging-cylinder, allowing the gases to iiow freely between them whenthe cock Gr' is opened. A pipe, B, provided with the cock b', leads fromthe cone Z' to the open air.

The piston U moves gas-tight in the charg ing-cylinder T when below theline of the lower edge of the charging hole or aperture c. It isconnected, by the piston-rod y, with the piston o, which latter moves ina hydraulic cylinder, V, of ordinary construction.

I is a vessel or purier, into which the pipe H leads, so placed thatparticles of fuel too large to float in the gaseous atmosphere in I(whereof hereinafter) will be dropped on the hollow inverted cone f,which forms its bottom, and pass into the lower chamber or cinder trapf" through the short pipe f'", which contains the cock f'. This cock isalways open, except when it is necessary to remove the cinders from thecinder-trap f", in which case it is closed. J is a pipe communicatingfrom the cinder-trap .with the open air, and provided with a cock, J',which is always open when cock f' is closed. g and h are man-holes, theformer for the ptupose of repairs and the latter for the removal of thecinders from the cinder-trap.

The pipe K forms a communication between the purifier and the converter0 through the medium of the pipe Q, the circular pipe Z, the branchpipes b b b b, and the tuyeres d d.

The lower end of the pipe Q is connected, by the elbow W, with the pipeZ, and has in it a cock,W'.

The converter O, of the shape represented in the drawing, is journaledupon hollow trunnions Bx Bx", from one of which, B", leads the pipe Q,which communicates with the pipe Z, and from the other, B* x, the pipeS, communicating with the pipe Y, which is fed with an air-blast fromthe pipe It itself, leading direct from the main blast-pipe Dx from theengine, as shown in Fig. 5.

The pipes K and It communicate direct with the trimnions.

The lower end of the pipe S is provided with a cock, X', and connectedby an elbow, X, with the pipe Y.

The pipes a a, &c., connect the upper pipe Y, and the pipes b b b, &c.,connect the lower pipe Z, 4with the chambers c c, &c. These chamberscommunicate with the interior of the converter through the holes d d,&c., in the tuyeres, Wgr are fixed gas-tight in the sockets above thechambers c c c, Src. They are firmly fixed in the upper plate a' of thecylindrical chainber I), which incloses the pipes Y and Z and branchpipes leading to the tuyeres d d. This cylindrical chamber is connectedby any convenient means to the converter. The space between the plate xand the bottom of the converter is filled with moistened fire-clay orother suitable material.

The bottom is movable, and connected with the sides by bolts and keys orother devices.

M is the carbon-receiver-an air-tight vessel of any form, provided thatits lower end tapers toward a point and ends in a pipe, in which a cock,t, is placed. The lower part of this pipe is curved after entering thepipe K, and ends in a conical nozzle, fv. N is a pipe, 011e end of whichopens into the pipe K, and the other in an agitator or perforatednozzle, N', in the carbon-receiver M. i

The object of the perforatednozzle is to keep the powdered carbon inalstate of agitation, and insure a consta-nt and steady flow into thepipe K and through vthe ,trvlmnion B", and thence through the tuyeres dLd,`wl1en the cock t is opened. 0n the other side of the converter is afiuX-receiver similar in every respect to the carbon-receiver described,and for a similar object. Withontithese nozzles the carbon or ux wouldpaclnand not blow out steadily.

Such being the mechanical construction of my apparatus, the following.is the mode of operating its various parts.

The generator is charged with any common fuel, as follows: The pistonU,Fig. 1,is lifted a little above the aperture@ in the charging-cylinder Tby the movement of the piston o inthe hydraulic cylinder V, the valve E'bein g closed. The ch arging-cylinder T is then `filled with fuel towithin a few inches of the lower" edge ofthe aperture e, and `the pistonUllowered upon it, so as to cut off all commimica 'onfbetween the lowerpart of the cylinder Ta the apertm'e e. Thecock b' is now closed andopened, allowing any gas in the gener 5 to flow into that portion of thecharging, "derwhich is below the pist-on U, .thus eq al1' ng thepressure above and below the ve? E', which is then drawn back by theever G'irother device, and the fuel allowedgto fallintothe generator A.The cock G is .then closed, ,and the piston forced down to thejunctionoffthe cylinder with Z', and the valve E' pushed forward,thereby intercepting connn'ulcation Y between A and T. The cock b' isnowiopened, and the gas in Z between the piston Uy andthe valve E'permitted to escape into the The pis ton U is now raised abovethe `upperedge of the aperture e, and the process of charging repeated.

If the fuel jams in Z', it can beloosened by the poker F operated by thelever F'.

When it becomes necessary to clean out the generator the cock H' isclosed, and the gas allowed to escape through. 1)' or c by opening thecock G when the piston U is at its highest position.K The movable'bottomSX Iisthen detached, permitting Vthorough cleaning.

When necessary to remove the cinders-from the cinder-trap f", orlowerpart of the-purifier I, the cock f must be4 closed and the cock Jopened. As soon as the pressure ofthe gas in the cinder-trap is equal tothat of the atmosphere the man-hole 71J is opened and .the cindersremoved. The man-hole h and the cockA J are then closed, asfbefore, andthe cock j" opened, so that the cinders may again fall into thecinder-trap.

It will be observed that I construct the valve E of the generator A asdescribed, so that afterthe cock G has been closed and b' opened thepressure of gases in the lgenerator holds the valve tightly up againstits case, tightly closing up the generator, andpreventing the retractionof the valve without considerable force, and also the escape of gases 5"but when the cock G' is again opened the circulation of gases from thegenerator into the charging cylinder establishes an equilibriumofpressure throughout the two, andr permits the easy retraction of thevalve E. After the charging operations in the generator are completedthe man-holes g and h in the purifier, Fig. 1, are closed and luted, theman-hole i inthe generator and all the cocks leading to the `openair-are opened, the valve E is closed, and the fuel ignited throughthemanhole t'.

As soon as the fire has spread, this man-hole is closed, luted, and rmlyflxed.- A gentle blast is then put on, and the heat gradually increaseduntil it becomes safe to use a full blast.

The converterO must be gradually heated before charging, whereofhereinafter.

All the cocks are then closed, except H and j", until the gases in thegenerator attain the desired pressure. r

The gases formed in the generator are nitrogen, carbonicoxide, andhydrocarbons,the last-named gases being distilled in the upper part ofthe generator.

The formation of the other gases may be described as follows:` Airiscomposed of two gases-nitrogen and oxygenthe latter of which combineswith carbon at ahigh temperature, setting the nitrogen free. It formstwo combinations with carbon, viz., one equivalent of carbon to oneofAoxygen forming carbonic oxide, and one equivalent of carbon to two ofoxygen forming carbonio acid;

These gases pass vvery readily from one to the other'at a hightemperature, according as oxygen or carbonis present in excess. Hence itis evident that at the point of the tuyeres in the generator, where `theoxygen of the blast is in excess, carbonic acid must always be ibrmed,and also that as this. gas passes up through the incandescent fuel itwill combine with an additional equivalent of carbon, and becomecarbonio oxide, in which form it will pass into the purifier and throughthe pipes, to the chambers c c c imder the tuyeres in the converter,where it again meets the oxygen of the blast through the air-pipes R S Xy a, and, mingled with that blast, passes up into the converter. As soonas the mingled blast encounters the high temperature at the point of thetuyeres in the converter it is decomposed, the nitrogen being, asbefore, set free, and the oxygen combining with the carbon in thecarbonio oxide, forming again carbonio acid, and generating intenseheat.

When charging the converter the bottom is first covered with a thinlayer of ignited fuel, and on this is placed the ore to be converted,broken into small pieces, and spread as evenly as possible over it. Avery gentle air-blast is then put on through the blast-pipe R, so as tocause the fuel in the bottom to burn to ame. The cock W' is thengradually opened, permitting streams of carbonated gases through thepipes b b to meet those of atmospheric air through the pipes a a, andcommingle in the chambers c c, whence they pass up the tuyeres d d inamixed condition, and, colning into contact with the ame of the ignitedfuel in the bottom of the converter, ignite and turn to carbonio acid,generating an intense heat by the oxidation of carbonated gasessufticient to melt even malleable iron. By the heat thus generated theore is fused. After fusion is completed the atmospheric air is cut offby closing the cock X', and the tlow of carbonated gases through themolten mass continued until the ore is reduced, the carbonic-acid gasformed escaping through the throat.

In order to facilitate this latter part of the operation,the cock t isopened, permitting the powdered carbon previously placed in the receiverto pass out through the nozzle, and, borne on by the current of thegases, to pass up with it into the molten mass and combine with the.oxygen in it, and thereby assisting in the deoxidation of the ore.

The ore thus reduced may now be iiuxed by such agents in the powdered orgaseous state as may be found most desirable.

The receiver SX X being used to contain the powdered iiux which iscarried through the tuyeres d d d by means of the air-blast, if the orecontains any very considerable percentage of foreign matters, such assilica, Sac., it may be found economical to use the carbonated gases asthe vehicle or means by which the i'lux is carried into the moltenmetal, using the carbon-receiver or its duplicate on the same side forthe flux; but if the ore contains only a small percentage of foreignmatters it can be fluxed from the flux-receiver proper, located as shownin the drawings, using air as the vehicle or means by which it iscarried into the molten metal through the tuyeres (l a. If air be used,when the quantity of impurities is large there is danger of waste by theformation of silicates, &c. On the other hand, if the gases are made thevehicle, when the quantity of impurities is small there will be a wasteof fuel in generating the gases for that purpose. An analysis of the orewill determine which should be used. But it may happen, from one causeor another, that the temperature of the bath has been somewhat reducedbelow the intense heat required. In this case the air and gases must beused at the same time, in order to restore the lost heat, the air beingthe vehicle by which the tiux is carried into the metal.

The mechanical arrangelnents are such as to meet any of those cases.

The ore being thus reduced and luxed, the converter is turned on itsside sutticiently t-o allow the einder or slag to tlow into a ladle orother vessel prepared for that purpose.

After the slag is removed the converter is brought again into thevertical position, and a stream of atmospheric air sent through themolten metal, (the full pressure of blast is put 011 just before theconverter begins to move toward the vertical,) in order to remove anycarbon that may have been in excess of that required for reduction ordeoxidation, so that the proper quantity of carbonic oxide and carbonrequired to cause the desired degree of hardness may be accuratelydetermined.

When thus purified the metal can be carbmized to steel of any degree ofhardness desired by cutting` otf the atmospheric air and sending throughthe molten metal a determined weight of powdered carbon from therefilled carbonreceiver in streams or jets of carbonated gases tlowingfor a definite time. When this last part ofthe operation is completedthe converter is turned on its side, the cocks closed, and the steelpoured into ladles, ready for casting into ingots or molds of anyrequired shape.

When scrap-iron pig is to be changed into steel, it must be broken orcut into small pieces and spread in the converter, as in the case of theore, on a layer of ignited fuel. In this case carbonated gases should bein excess in the fusing-flame, a part only ot that gas being` biuned tocarbonic acid, thereby avoiding the waste that would ensue from theoxidation of the metal if all the carbonic oxide were burned to carbonioacid. The removal of the impurities, if any, and the nal carburizationof the metal into steel, are accomplished by silnilar means to thoseemployed in the case of metal made direct from the ore.

When the ore or metal contains phosphorus or sulplnn, and it isconsidered desi 1able to use carbonio oxide as the vehicle by which theregular ux is carried through themolten mass, the agents-such aschlorine, chloride of sodium, Src-used for the removal ot the aboveimpurities must be employed after the iiuxing of the other impurities iscomplete, and should be carried through the molten metal by atmosphericair or earbonic-aeid gas; but ifthe regu lar flux is carried into themetal by either atmospheric air or carbonie-aeid gas, the agents usedfor the removal of the phosphorus or sillphur may be mixed with it, andall the impurities acted upon at the same time.

If gases are used as fluxes, instead of powder, for the removal ofphosphorus or sulphur, they are put into a gas-receiver similar to thelinx-receiver, and blown through the tuyeres, and thence through themolten mass, by a blast of atmospheric air or carbonio-acid gas.

If the steel is made by the ordinary process now in use, and it is onlynecessary to remove they phosphorus or sulphur, the generator andgas-pipes maybe dispensed with, the air-pipes alone being necessary.

The cocks W and X are to be gradually, not suddenly, opened. l

I do not claim, broadly, recarburizing the metal by blowing in powderedcarbon through the tuyeres by aid of a motive blast, but by aid of ablast of carbonio-oxide gas, as set forth and claimed in clause 9.

The following are the claims which I make:

1. The combination of the genera-tor A, the charging-cylinder T, thevalve E', and the equalizing-pipe G.

2. In combination with the charging-cylinder T and the generator A, theescape-pipe B and pipe G, for the purpose specified.

3. The combination, with the cylinder T, of the piston U and thehydraulic piston O, connected therewith by the piston-rod y, andinclosed in the cylinder V.

4. The perforated nozzle N', in combination with the carbon-receiver Mto agitate the carbon contained in saidreceiver, so as to cause it toflow regularly 'om the same.

5. The combination of pipe K, pipe Z, branch pipes 11, and chambers c,substantially as and for the purposes set forth.

6. The combination of pipe R, pipe Y, branch pipes a, and chambers c,substantially as and for the purposes set forth.

7. In combination with tuyeres d, the chambers c, whereby the commixtureof atmospheric air and carbonic-oxide gas prior to their passage throughthe tuyeres into the converter is effected.

8. The process of reducing iron from its ores, which consists in forcingcarbonio-oxide gas, with or without carbon, through a molten mass of theore contained in a converter until the metal is reduced, and theninjecting ilux to separate it from the gangne, as described.

9. The process of carbonizing molten iron in the converter by jets ofcarbonio-oxide gas, with powdered carbon blown through the tuyeres intothe converter.

In testimony whereof I have hereunto signed lny llllle.

M. J. HAMILTON.

In the presence of- J. BoNsALL TAYLOR, W. C. STRAWBRIDGE.

